BR40 bulbs not all the same size?

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Old 01-23-19, 05:11 PM
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BR40 bulbs not all the same size?

Replacing a bulb in a ceiling can fixture in a 50 year old house. Removed the old CFL BR40 bulb and got a new BR40 LED. It wont fit. 10cm wider than the old one. WTH? Aren't bulb sizes standard?
 
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Old 01-23-19, 05:28 PM
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The BR 40 refers to the base size and thread. The actual glass size and shape may vary from manufacturer to manufacture. Where LED bulbs are concerned they tend to be a bit bigger due to the fact that room must be accommodated in the base for electronics. So yes it may be just a tad higher or longer in length.
 
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Old 01-23-19, 05:34 PM
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Well, even a conventional plain old bulb screws into the base. Didn't think I will have to measure every bulb in the store for fit.
 
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Old 01-23-19, 05:35 PM
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CFL's and LED's are rarely the same size.
LED's are also larger in the base than standard incandescent A lamps.

A conventional bulb will usually be the smallest available in physical size.
 
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Old 01-24-19, 04:04 AM
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I am sure you have heard the expression "mixing apples and oranges". You chose to replace a fluorescent with a LED so blame the person in the mirror.
 
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Old 01-24-19, 04:49 AM
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When CFL first came out everybody said they were a direct replacement for their incandescent predecessors. Same when LED came out.
 
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Old 01-24-19, 09:44 AM
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I think we're beating a dead horse here.
 
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Old 01-24-19, 11:08 AM
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The Shapes: BR30 and BR40

Let’s start by understanding the terminology. In the names of these bulbs, BR refers to a bulged reflector; this shape is used to evenly spread light, which is why these are used for general lighting.

https://blog.lightingsupply.com/blog...ed-light-bulbs


The 30 or the 40 refers to the diameter of the lamp in eighths of an inch so a BR40 has a diameter of 40/8 of an inch or 5". A BR30 would have a diameter of 30/8 or 3 3/4".

BR lamps all have a medium base.

Removed the old CFL BR40 bulb and got a new BR40 LED. It wont fit. 10cm wider than the old one. WTH? Aren't bulb sizes standard?

There has always been a certain amount of standardization in lamp sizes and shapes, but today most lamps are manufactured in China and all bets are off.
 
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Old 01-24-19, 11:56 AM
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The 30 or the 40 refers to the diameter of the lamp in eighths of an inch so a BR40 has a diameter of 40/8 of an inch or 5".
Except this bulb is 5 1/4" or nearly a half inch wider than the BR40 bulb that previously fit just fine.
 
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Old 01-25-19, 05:48 AM
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Old 01-25-19, 05:55 AM
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According to that I could probably use PAR38 instead of the BR40.
 
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Old 01-26-19, 07:11 AM
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Except this bulb is 5 1/4" or nearly a half inch wider than the BR40 bulb that previously fit just fine.

Than what you have is not a true BR40. What brand is it and where was it made?


According to that I could probably use PAR38 instead of the BR40.

Yes, it should fit the fixture, but PAR38 lamps generally don't have as pleasing effect as reflector floods although they are sometimes used indoors. You could also use either a BR30 or ER30.
 
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Old 01-26-19, 07:18 AM
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It's a CREE and made in China like most.
 
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